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Polymerization of Methyl Acrylate and As Comonomer with Ethylene Using Single-Site Catalysts

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Polymerization of Methyl Acrylate and As Comonomer with Ethylene Using Single-Site Catalysts Rochester Institute of Technology RIT Scholar Works Theses 3-1-2008 Polymerization of methyl acrylate and as comonomer with ethylene using single-site catalysts Sameer S. Vadhavkar Follow this and additional works at: https://scholarworks.rit.edu/theses Recommended Citation Vadhavkar, Sameer S., "Polymerization of methyl acrylate and as comonomer with ethylene using single- site catalysts" (2008). Thesis. Rochester Institute of Technology. Accessed from This Thesis is brought to you for free and open access by RIT Scholar Works. It has been accepted for inclusion in Theses by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. Polymerization of Methyl Acrylate and as Comonomer with Ethylene Using Single-Site Catalysts By Sameer S. Vadhavkar A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science in Materials Science and Engineering Approved by: Prof. __________________________________________ Dr. Massoud Miri (Thesis Advisor) Prof. __________________________________________ Dr. KSV Santhanam (Head of Department) CENTER FOR MATERIALS SCIENCE AND ENGINEERING COLLEGE OF SCIENCE ROCHESTER INSTITUTE OF TECHNOLOGY ROCHESTER, NEW YORK MARCH 2008 1 Polymerization of Methyl Acrylate and as Comonomer with Ethylene Using Single-Site Catalysts By Sameer S. Vadhavkar I, Sameer S. Vadhavkar, hereby grant permission to the Wallace Memorial Library of the Rochester Institute of Technology to reproduce this document in whole or in part that any reproduction will not be for commercial use or profit. _______________________ _______________________ Sameer S. Vadhavkar Month, Date, Year 2 ROCHESTER INSTITUTE OF TECHNOLOGY This volume is the property of the Institute, but the literary rights of the author must be respected. Please refer to permission statement in this volume for denial or permission by author to reproduce. In addition, if the reader obtains assistance from this volume, he must give proper credit in his own work. The following persons, whose signatures attest to their acceptance of the above restrictions, have used this thesis. Name Address Date 3 DEDICATION I would like to dedicate this work to my parents, Dr. Savita Vadhavkar and Sunil Vadhavkar, without whom I would not be where I am today. 4 ACKNOWLEDGEMENTS I would like to thank my advisor, Prof. Massoud (Matt) J. Miri, for his valuable guidance and support. His passion for chemistry and commitment to excellence has made my time at the Rochester Institute of Technology a truly remarkable experience. I would also like to thank the members of Dr. Miri’s group both past and present. In particular, the friendship and enthusiasm of Matt Fullana and James Soucy ensured that each day was not only productive, but also enjoyable. Also would like to thank one of my research group members, Nikhil Kolhatkar, who has helped me a lot with my experimental part. I would also like to thank my committee members Dr. Gerald Takacs and Dr. Thomas Smith for their time and research suggestions. This research work was supported by the University Affairs Committee foundation grant of Xerox Corporation. So I would like to thank Dr. G. Sacripante of the Xerox Research Centre of Canada for his support. The GPC measurements were made by Dow Chemical Corporation, so I would like to thank Dr. Peter Nickias for providing the data. Finally special thanks to my parents, Dr. Savita Vadhavkar and Sunil Vadhavkar and my brother, Swapnil Vadhavkar. My accomplishments have only been possible with their support, and this thesis stands as a testament to their dedication. 5 ABSTRACT Title of Document: POLYMERIZATION OF METHYL ACRYLATE AND AS COMONOMER WITH ETHYLENE USING SINGLE-SITE CATALYSTS Sameer Sunil Vadhavkar, Master of Science, 2008 Advisory Committee: Dr. Massoud (Matt) Miri, Dr. Thomas W. Smith Dr. Gerald A. Takacs Because of the excellent control over polymerizations provided by single-site catalysts (SSCs), numerous research groups are trying to find such catalysts, which would also be efficient for the polymerization of polar monomers. However, many SSCs are deactivated by undergoing reactions with the electronegative atoms in the polar groups. In the present work, we attempted to copolymerize ethylene with methyl acrylate using three SSCs: (1) a bis(imino)pyridyl iron(II) chloride / methylaluminoxane catalyst, (2) a chiral metallocene / tris(pentafluorophenyl) borane catalyst, and (3) an in situ trifluromethyl substituted nickel (II) enolate catalyst. Only the first two catalysts led to polymer formation. The metallocene had relatively low activities and formed polymethyl acrylate. The most efficient catalyst for the synthesis of the copolymers was the iron- based catalyst 1. The ethylene consumption indicates that its activity reaches a maximum after which it steadily declines. By kinetic measurements, 1H and 13C NMR spectroscopy and the measurement of glass and melting temperatures, we could show that copolymers of ethylene and methyl acrylate were not formed. The products formed were blends, of high density polyethylene and methyl acrylate. Homopolymerizations of methyl acrylate using the three catalyst systems were also studied. Again it was found that the catalyst 1 had the highest activities. Atactic polymers were formed. There was a clear dependence of the activity and molecular weight on the Al/Fe-ratio, which indicates that the polymerization mechanism is coordinative and not initiated by radical species. 6 MAIN RESEARCH GOALS AND SUMMARY OF RESULTS The main goal of this research is to find a single-site catalyst system, which can form copolymers of ethylene and methyl acrylate. Single-site catalysts represent the most recent generation of Ziegler/Natta catalysts, which in contrast to the latter only form one active catalytic species. Copolymers of ethylene with polar monomers are used as adhesives, paints and compatibilizers. Historically, these copolymers have only been prepared by free-radical copolymerization. Now there is potential for the use of coordination systems as well (i.e. single-site catalyst). Single-site catalysts not only provide an excellent control over tailoring properties of polyolefin but also provide better incorporation with higher yields. The single-site catalysts based on late transition metals appear to be more stable towards polar group monomers. For our experiment we are considering a modified metallocene catalyst, an iron based bis(imino)pyridine catalyst and a nickel(II)enolate. Our work also includes characterization of the copolymers by IR, 1H NMR, 13C NMR, TGA, DSC, and GPC, the latter provided by Dow Chemical. In this work, the homopolymerization of methyl acrylate (MA) and its attempted copolymerization with ethylene using three single-site catalysts is described. The primary catalyst under investigation is formed from a bis(imino)pyridine iron(II) chloride with methylaluminoxane (1), which is compared to bis(4,5,6,7-tetrahydro-1-indenyl)zirconium dimethyl / tris(pentafluorenyl)borane) (2), and a P,O-chelated nickel(II) enolate catalyst (3). Catalyst (1) leads to the highest activities exceeding those of catalyst (2) by a magnitude. Catalyst (3) results in formation of no polymer. The kinetics of the 7 polymerizations and the effect of the Al/Fe-ratio and temperature on the activity and molecular weight of the polymers have been determined. In the ethylene/methyl acrylate copolymerization trials, catalyst (1) produces a blend of the two homopolymers, polymethyl acrylate (PMA) and polyethylene, catalyst (2) forms PMA only, and catalyst (3) results again in no polymer formation. Remarkably, using catalyst (1) it is possible to produce polymer blends with up to 52 % PMA at high activities. The polymerization kinetics has been determined based on the directly measured uptake of ethylene during the runs. 1H NMR and DSC have been used as efficient methods to prove that polymer blends instead of true copolymers were formed. Finally, the polymerization mechanism will be discussed. 8 TABLE OF CONTENTS Dedication............................................................................................................................4 Acknowledgement...............................................................................................................5 Abstract................................................................................................................................6 Main Research Goals and Summary of Results ..................................................................7 Table of Contents.................................................................................................................9 List of Figures....................................................................................................................10 List of Schemes..................................................................................................................12 List of Tables.....................................................................................................................13 Chapter I – INTRODUCTION TO ZIEGLER-NATTA CATALYSTS.......................................14-34 History and Introduction....................................................................................................15 Evolution of Single-Site Catalysts......................................................................................17 Chapter II – EXPERIMENTAL PROCEDURE.....................................................................35-50
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